1. Field of the Invention
The present invention relates to image generating apparatuses and image generating methods which are used to generate an image for, e.g., inspecting the orientation of an electronic component mounted on a substrate.
2. Description of the Related Art
An inspection apparatus that inspects the orientation of an electronic component placed on a tray is disclosed in Japanese Patent Application Publication No. JP-A-2009-76796. The electronic component has a mark such as a character, a symbol, or a pattern on its upper surface. The mark is typically white, whereas the upper surface of the electronic component is typically black. Thus, average luminance varies between an area with the mark and an area without the mark. Accordingly, the positional relationship between these areas can be determined based on the respective average luminance values of these areas, and the orientation of the electronic component can be determined based on the positional relationship between these areas.
In the inspection apparatus of Japanese Patent Application Publication No. JP-A-2009-76796, however, the accuracy of determining the orientation is low in the case where an image that is used to calculate the average luminance values has low contrast.
Inspection of the orientation is performed not only on an electronic component placed on a tray but also on an electronic component mounted on a substrate. When the image has low contrast, the operator changes lighting conditions (e.g., a lighting color) of a lighting apparatus for an imaging operation, changes the shutter speed of an imaging apparatus, and so forth by trial and error in order to increase the contrast. Accordingly, it takes time to increase the contrast.
The operator needs to be skilled in order to appropriately set the lighting conditions, the lighting color, the shutter speed, and the like. Accordingly, depending on the operator's skill, the inspection apparatus may determine that the orientation of the electronic component is wrong, even if it is actually correct, or the inspection apparatus may determine that the orientation of the electronic component is correct, even if it is actually wrong. That is, if the operator is not so skilled, the probability of such erroneous determination of the inspection apparatus increases. Namely, the accuracy of detecting abnormalities of the electronic component decreases. Moreover, the detection accuracy varies depending on the operator's skill.